I have mixed feelings on this -- and I must admit I haven't given it a whole lot of thought. On the one hand, I grasp that when a company advertises something, they should deliver. And it's good to hold corporations to such things.
First, at best, this strikes me as more an Federal Trade Commission sort of thing, not lawsuit world. Besides, how much does it cost to pursue a lawsuit, all for the sake that your sandwich might have been an inch short?
Also, there are a lot of things worth getting up in arms in this life over. A sandwich maybe being an inch short sometimes doesn't make the list.
And also, the company notes that "Footlong" is intended more descriptive than specific. Mind you, I'm not completely sure I buy that explanation, but there are plenty of things that are described one way and meant only as a description, not reality. I don't think someone is likely to drink a Big Gulp in just one huge sip. Besides, they have a Trademark insignia after the name Footlong™ -- which says to me, whatever their intent, that is...well, a Trademark. Not a stand-in for a ruler, should you lose yours.
Also, regardless of the length of the bun, you can tell the server to keep piling on most anything for your sandwich you want. I've asked for extra pickles and olives, and they happily keep adding them. However, long the bread is. So, customers aren't necessarily losing an inch of sandwich on the times when the bun is short, just an inch of bread. (See point #2: prioritizing what to get up in arms over.)
I have no problem with the subject being addressed with Subway. And no problem with the FTC making inquiries and resolving what Subway is doing and trying to do. And do think that something called a "Footlong™" ideally should be a foot long. But angst and lawsuits? I think some people have lives that are too empty trying to find meaning in the wrong places...or are hoping to be paid off to go away.